1. Field of the Invention
This invention relates to a method and an apparatus for supplying a label in an in-mold labeling system to a pseudo core so as to be placed in position in the inside of a metal mold by the pseudo-core at a high level of accuracy. The method and apparatus are applicable in a label insert molding operation including the step of molding synthetic resin integrally with a label placed in position in a metal mold and wherein the label has a desired design of letters and/or a graphic printed thereon.
2. Description of the Related Art
Known techniques in the field of label insert molding where products such as cups, containers and etc. are produced by molding integrally with a label on the surface, the label carrying a desired design of letters and/or a graphic printed thereon, include the one disclosed in Japanese Patent Application Laid-Open Publication No. 5-285981. According to the patent document, a label is wound around a pseudo-core showing an outer profile exactly agreeing with that of the expected molded product and having a large number of suction pores on the outer surface thereof. Then, the label is drawn and held in position around the pseudo-core and the pseudo-core is brought into the metal mold with the label wound around it. Subsequently, the label is released from the drawn and held state and inversely drawn to the metal mold so as to be placed in position in the latter.
When the label is held in the state of being wound around the outer surface of the pseudo-core with the above described label placement method, a longitudinally middle part of the uppermost layer of the multilayer label is brought close to a part of the outer surface of the pseudo-core and the label is drawn to the latter so that the label may be resiliently deformed by the suction force and wound around the entire outer surface of the pseudo-core.
However, the above described method is designed to draw the label along the longitudinal peripheral edges thereof so as to make it wound around the outer surface of the pseudo-core and hence requires the pseudo-core to exert a strong label drawing force onto the label. Therefore, it requires the use of a large negative pressure (vacuum) generating apparatus, which by turn makes the entire delivery system large and costly.
Additionally, when the label is resiliently deformed and wound around the outer surface of the pseudo-core, the attitude of the label, that of the longitudinal peripheral edges thereof in particular, can easily be distorted to make the label that, which is wound around the pseudo-core, very unstable. When the label is wound around, held by the pseudo-core in an unstable state and placed in position in the metal mold for molding, the label can easily be displaced relative to the molded product and/or creased to make the molded product a defective one.